JP4715119B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus that locally heats a surface of a processing object by a laser beam while scanning the surface according to a predetermined order, and heat-treats the surface of the processing object.

  In the manufacturing process of the liquid crystal panel, there is an annealing process in which amorphous silicon is formed on the surface of a transparent glass substrate using chemical vapor deposition (CVD), and this amorphous silicon film is annealed to be processed into a polysilicon film. .

In the laser processing apparatus of the prior art, the laser beam is focused in real time by applying feedback control to the target position difference while measuring the position with respect to the workpiece (Patent Document 1).
Japanese Patent Laid-Open No. 11-245067 (page 3, FIG. 1)

  Therefore, the conventional laser processing apparatus cannot be realized unless the measurement point and the processing point on the surface of the processing object are the same and temporally the same.

  Also, if fine dust is placed on the surface of the workpiece or there are points that cannot be measured, such as the edge of the workpiece, the laser beam may be out of focus and laser processing may not be performed properly. .

  The present invention is intended to solve these problems, and even when the measurement time and the processing time of the surface of the processing object are not the same, fine dust adheres to the surface of the processing object. In addition, a laser processing apparatus capable of performing laser processing using a displacement meter and laser processing means disposed at a predetermined interval even at a position near the end face of the processing object is obtained. With the goal.

Therefore, the laser processing apparatus of the present invention sequentially measures the height of the surface at different positions of the workpiece and collects height displacement data, and at least between the measurement points adjacent to the displacement meter. Laser processing means that emits a laser beam that is disposed at an interval and heats the surface of the object to be processed; and height displacement data measured and collected by the displacement meter to process the laser of the laser processing means a control data generating means for generating a control data suitable for the beam to be focused or offset on the front surface of the workpiece, and a focus control means for controlling the focus of the laser beam from the laser processing means in accordance with said control data It is configured with.
Then, when scanning the first line in the X direction from one end to the other end of the surface of the workpiece, the displacement meter is preceded by the laser processing means, and the displacement is reached when the other end is reached. While maintaining the positional relationship between the meter and the laser processing means, the scan direction is reversed by slightly shifting in the Y direction orthogonal to the X direction, and scanning is performed from the other end of the surface of the workpiece to the one end. In this case, the laser processing means is preceded by the displacement meter, and the second adjacent line different from the first line is scanned from the other end of the surface of the workpiece toward the one end. When the displacement meter scans prior to the laser processing means, the control data corresponding to each measurement point is measured while sequentially measuring the measurement points with the displacement meter. When the surface of the object to be processed is laser processed with the control data from the forming means, and the laser processing means scans in advance of the displacement meter, the control data is measured while sequentially measuring the measurement points with the displacement meter. The laser processing means stores the surface of the object to be processed with the control data from the control data generation means corresponding to each measurement point obtained when the previous line is scanned. It is characterized by processing.

The focus or offset of the laser beam on the surface of the workpiece by the control data of the focus control means in the laser processing apparatus is performed by finely adjusting the focusing lens incorporated in the laser processing means in the vertical direction. It is characterized by that.

  Further, the control data generation means in the laser processing apparatus removes the height displacement data of the abnormal value when an abnormal value occurs in the height displacement data measured and collected by the displacement meter. It has a filter function.

Further, the X direction and Y direction traces on the surface of the object to be processed by the displacement meter and the laser processing means in the laser processing apparatus move the XY axis stage on which the object to be processed is placed in the XY direction. , By performing control.

  Furthermore, the processing object in the laser processing apparatus is an amorphous silicon layer formed on a transparent glass substrate.

  Still further, the laser processing for the object to be processed in the laser processing apparatus is an annealing process.

  Therefore, according to the laser processing apparatus of the present invention, even if the surface of the object to be processed is inclined or warped, it is possible to adjust and irradiate such a surface with a laser beam, and thus to heat uniformly. Can do.

  Moreover, when the focus of the laser beam with respect to the surface of the workpiece is offset, the machining surface of the workpiece can be heated with a spot having a relatively large area.

  Furthermore, since the control data generating means has a filter function, even if there is an abnormal value in the height displacement data measured and collected by the displacement meter, the surface of the object to be processed becomes abnormal. There is no heating.

  According to the laser processing apparatus of the present invention, when accuracy is required, the accuracy can be improved by increasing the number of measurement points, and when the processing speed is important, the laser processing speed is decreased by reducing the number of measurement points. Can be faster.

  In addition, even if the surface of a workpiece such as a glass substrate is inclined and the height difference is, for example, a maximum of ± 150 μm, for example, if it is calculated and followed after measurement, it can be kept within ± 8 μm, for example. Effect.

  Furthermore, even if dust adheres to the surface of the object to be processed, even if the laser processed part is an end of the object to be processed, laser processing can be performed.

  As described above, in the manufacturing process of the liquid crystal panel, the amorphous silicon Wa is formed on the surface of the transparent glass substrate Wb using chemical vapor deposition (CVD), and the amorphous silicon layer Wa is annealed to form polysilicon. There is work to process the membrane. The laser processing apparatus 1 of the present invention was used as a laser annealing apparatus for an amorphous silicon layer (object to be processed) formed on the surface of this glass substrate.

  In order to change the amorphous silicon layer Wa to a polysilicon layer, accurate temperature control of heating by the laser beam Lb is necessary, and adjustment of the focus is indispensable. As will be described later in detail, a laser barrel 41 that emits a laser beam Lb is used as a processing point, and a laser displacement meter 3 is used to measure the height displacement of the amorphous silicon layer Wa. Then, after the height displacement of the surface of the amorphous silicon layer Wa is measured in advance, a focus operation is performed to perform a follow-up operation with control data generated based on the measurement data.

  The surface position of the amorphous silicon layer Wa on the glass substrate Wb is made into a two-dimensional array of XY coordinates, traced and measured by the laser displacement meter 3, and the surface displacement data is substituted into the calculation formula of the two-dimensional array. The data is stored, calculated and processed into Z-axis height data of the laser barrel 41, and the Z-axis of the laser barrel 41 is made to follow at the time of machining to adjust the focus of the laser beam Lb, and annealing treatment is performed. Is going.

  Hereinafter, the laser processing apparatus of this invention is demonstrated using figures.

  FIG. 1 is a conceptual diagram of a laser processing apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a method of tracing a laser displacement meter and a laser barrel with respect to the surface of an amorphous silicon layer on a glass substrate. 3 is a conceptual diagram for explaining the operation of the laser displacement meter and the laser barrel when tracing the first row of the surface of the amorphous silicon layer shown in FIG. 2, and FIG. 4 is a laser displacement meter and the laser barrel. FIG. 5 is a conceptual diagram for explaining the first positional relationship and operation between the laser displacement meter and the laser lens barrel when the trace of the laser beam moves from the first column to the second column. FIG. FIG. 6 is a conceptual diagram for explaining the second positional relationship and operation between the laser displacement meter and the laser column when the trace with the column shifts from the first column to the second column. In laser processing equipment 7 is a flow chart for explaining the operation of the laser displacement meter and the laser processing means, and FIG. 7 shows the focus state of the laser beam with respect to the processing surface, and FIG. FIG. 4B is a cross-sectional view showing a state in which the work surface is offset and focused slightly above the processing surface.

  In FIG. 1, reference numeral 1 denotes a laser processing apparatus according to an embodiment of the present invention. This laser processing apparatus 1 includes an XY axis stage 2, a laser displacement meter 3, a focus lens 42 for a laser beam Lb, a computer 5, a Z axis driving means 6, a Z axis stage 7 as a height adjusting means, and the like. .

  The workpiece W in this embodiment is an amorphous silicon layer Wa formed on the surface of a transparent glass substrate Wb, and is placed on the XY axis stage 2 so that the surface is horizontal. Placed and fixed.

  As shown in FIG. 2, the surface position of the amorphous silicon layer Wa is arranged in a two-dimensional matrix in the XY axis direction, and the intersection point P (00,00) to the intersection point P (n, m) are the surface of the amorphous silicon layer Wa. It was a place to measure the height.

  The XY axis stage 2 can be adjusted so that the workpiece W placed on the surface thereof is in a horizontal state, and is moved in the X axis direction and the Y axis direction by driving means (not shown).

  The laser displacement meter 3 irradiates the surface of the workpiece W with a laser beam, and outputs height data of the irradiation point to the memory 53 of the computer 5 from the difference in reflection time.

  The focus lens 42 is incorporated in the laser barrel 41 constituting the laser processing means, and is fixed to the Z-axis stage 7. The vertical movement of the Z-axis stage 7 adjusts the height of the focus lens 42. The focus of the laser beam Lb is adjusted.

  The computer 5 is a general computer and includes an interface board 51, a CPU 52, a memory 53, an HDD 54, etc., and processes the height data at each measurement point input from the laser displacement meter 3 to display the Z-axis stage 7. It functions as means for generating control data for controlling the Z-axis drive means 6 to be driven. In the memory 53, array position data corresponding to each XY coordinate position of the amorphous silicon layer Wa is written in advance. The HDD 54 is used when the workpiece W after processing by the laser processing apparatus 1 of the present invention is evaluated.

  A laser displacement meter 3 and a laser barrel 41 are disposed and supported above the amorphous silicon layer Wa. The laser displacement meter 3 is spaced from the laser column 41 by at least a distance between adjacent measurement points, and is disposed in advance of the laser column 41. The two are paired together in the first row line. Trace on the line in each column. In this embodiment, the laser displacement meter 3 and the laser barrel 41 are fixed in the XY axis direction, and the XY axis stage 2 is controlled and driven in the X axis direction and the Y axis direction, so that the amorphous silicon layer Wa. Is moved in the XY-axis direction to trace its surface.

  Next, the operation of the laser processing apparatus 1 of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 3, tracing starts from the first column. FIG. 3 shows only the first column shown in FIG. 2, and shows the trace state of the first column. FIG. 3A shows a state in which the laser displacement meter 3 has reached the position P (00, 00) point on the amorphous silicon layer Wa and the laser barrel 41 has not yet reached the measurement position P (00, 00) point. The laser displacement meter 3 measures the height displacement of the surface of the amorphous silicon layer Wa at the measurement position P (00, 00), and substitutes the height data into the two-dimensional array of the memory 53.

  FIG. 3B shows that the laser displacement meter 3 further reaches the next measurement position P (00, 01), measures the height displacement of the surface of the amorphous silicon layer Wa at the measurement position, and stores the height data in the memory 53. Is assigned to the two-dimensional array. However, the laser barrel 41 has not yet reached the first measurement position P (00,00) point.

  FIG. 3C shows a state in which the laser displacement meter 3 has passed the measurement position P (00,01) point and the laser barrel 41 has just reached the measurement position P (00,00) point from the state of FIG. 3B. In this state, the array position data and height data corresponding to the measurement position P (00, 00) point measured by the laser displacement meter 3 in the state of FIG. 3A are read from the memory 53 and calculated and processed by the CPU 52. Z-axis height data of the Z-axis stage 7 is input to the Z-axis driving means 6 that drives the focus lens 42 of the laser barrel 41. The focus lens 42 of the laser barrel 41 is adjusted such that the Z-axis driving means 6 is moved up and down in accordance with the value of the height data to focus the laser beam Lb at the measurement position P (00, 00). I do.

  Hereinafter, the laser displacement meter 3 traces the measurement position P (00, 02) point, P (00, 03) point, and so on, to the measurement position P (00, m) point (FIG. 2) at the other end. Trace and measure the height displacement of those surfaces, write each height data in the memory 53 sequentially in a two-dimensional array, and sequentially process the memory when the laser barrel 41 reaches the measurement position P sequentially. The array position data and the height data are read from 53 and calculated by the CPU 52, and the height of the focus lens 42 of the laser barrel 41 is adjusted by the height data corresponding to each height displacement.

  When the laser displacement meter 3 and the laser column 41 have finished tracing the first row in this way, the laser column 41 is reversed while maintaining the positional relationship following the laser displacement meter 3, and is shown in FIG. 4A. Thus, the measurement position P (01, m-1) point, P (01, m-1) point,... P (01,00) in the second column in a state where the laser barrel 41 follows the laser displacement meter 3. When the laser barrel 41 reaches each measurement position P, the height displacement is measured at each measurement position P in the same manner as described above, and the height data is calculated based on the measured value. The height of the focus lens 42 of the laser barrel 41 is adjusted to perform annealing.

  When the measurement of the second row, the focus adjustment, and the annealing process are completed, the laser column 41 is reversed while following the laser displacement meter 3, and the third row is similarly traced. Hereinafter, the inversion is repeated and traced until the nth column while the laser barrel 41 follows the laser displacement meter 3.

  If the laser barrel 41 is reversed so that the laser barrel 41 follows the laser displacement meter 3, the support mechanism between the laser displacement meter 3 and the laser barrel 41 becomes complicated and the reversing operation takes time. There is a disagreement that it takes too much time to anneal the single amorphous silicon layer Wa.

  Next, a method for solving this problem will be described with reference to FIG.

  The positional relationship between the laser displacement meter 3 and the laser barrel 41 shown in FIG. 5 is reversed while maintaining the positional relationship between the two when the first column trace is completed, and the second column is traced. Let In other words, the laser column 41 precedes and the laser displacement meter 3 follows the laser column 41, and the second row is traced.

  Assuming that the annealing process is performed based on the positional relationship between the laser displacement meter 3 and the laser barrel 41, the laser displacement meter 3 follows the laser barrel 41 at the measurement position P (01, m), P (01, Since the m-1) point, the P (01, m-2) point,... are sequentially measured, the adjustment of the height position of the preceding laser barrel 41 is meaningless.

  Therefore, when the annealing process is performed in this positional relationship, when the laser displacement meter 3 is measuring the height of each measurement position P in the first row, the height data is set in the next row, that is, In the case of FIG. 5, the height data of each measurement position P in the second row is arranged and substituted in the memory 53, and the laser column 41 is placed at the measurement position P (01, m) in the second row. When it reaches, the focus lens 42 of the laser column 41 is adjusted using the height data of the measurement position P (00, m) point in the first row, and annealing is performed. When the measurement position P (01, m-1) point in the second row is reached, the height data of the measurement position P (00, m-1) point in the first row is used to determine the position of the laser column 41. The focus lens 42 is adjusted and annealed. Similarly, the height data of the measurement positions P (00, m-2), P (00, m-3),... Then, the focus lens 42 of the laser barrel 41 is adjusted, and annealing is performed by this method.

  Strictly speaking, this method does not mean that the focus adjustment of the laser beam Lb is precisely performed, but actually, since the height data of the very adjacent positions is used, the annealing process of the amorphous silicon layer Wa is performed. Will not cause any trouble. The tracing time of the laser displacement meter 3 and the laser barrel 41 can be shortened, and the support mechanism for them can be simplified.

  In the adjustment of the focus of the laser beam Lb based on the height data, as shown in FIG. 7A, the focus lens 42 is moved up and down by controlling the height of the Z-axis stage 7, and the laser beam Lb is moved. However, it may be adjusted so that it is focused on the surface of the amorphous silicon layer Wa. Alternatively, as shown in FIG. B, the laser beam Lb is adjusted so that it is focused slightly above the amorphous silicon layer Wa. Also good.

  In the former case, the spot on the surface of the amorphous silicon layer Wa irradiated with the laser beam Lb is minimized, and the edge becomes clear. In the latter case, the edge of the spot irradiated by the laser beam Lb is blurred, but the spot becomes large. Therefore, a wider range can be annealed than in the case of the former just focus. However, in this case, it is necessary to slow down the trace speed so that a sufficient heating temperature can be obtained.

  Next, the operation of the laser measuring unit (displacement meter 3), the operation of the laser processing unit (lens barrel 41), and the relationship between them will be described with reference to FIGS.

  The XY axis stage 2 is actuated (step S2), and tracing is started from the first row by the laser displacement meter 3 and the laser barrel 41. As shown in FIG. 3A, the laser displacement meter 3 reaches the position P (00, 00) point on the amorphous silicon layer Wa, and the laser barrel 41 still reaches the measurement position P (00, 00) point. In the absence, the laser displacement meter 3 acquires the current XY coordinates (step S11), and the current XY coordinates are converted into corresponding array data (step S12). Steps S11 to S13 are repeated until the laser displacement meter 3 reaches not only the measurement position P (00, 00) point but also another measurement position P.

  When the laser displacement meter 3 reaches the measurement position P (00, 00) point, the height displacement of the surface of the amorphous silicon layer Wa at the measurement position P (00, 00) point is measured (step S14). The surface height data is substituted into the two-dimensional array in the memory 53 (step S15).

  As shown in FIG. 3B, when the laser displacement meter 3 further reaches the next measurement position P (00,01) point, the current XY coordinates are similarly converted into corresponding array data. Then, the height displacement of the surface of the amorphous silicon layer Wa at the measurement position is measured, and the height data of the surface displacement is substituted into the two-dimensional array. However, the laser barrel 41 has not yet reached the first measurement position P (00,00) point. Accordingly, during this time, the laser barrel 41 does not currently acquire the XY coordinates, and there is no change in the arrangement position, so the operations from step S21 to step S23 are repeated.

  Next, as shown in FIG. 3C, when the laser displacement meter 3 passes the measurement position P (00,01) point and the laser barrel 41 reaches the measurement position P (00,00) point, its current XY The coordinates are acquired (step S21) and converted into an array position corresponding to the current XY coordinates (step S22). Since the array position has changed (step S23), the height data previously measured by the laser displacement meter 3 with respect to the array position is read from the memory 53, calculated and processed by the CPU 52, and the Z-axis of the Z-axis stage 7 (Step S24) and output to the Z-axis drive means 6 for driving the focus lens 42 of the laser barrel 41. As described above, the focus lens 42 of the laser barrel 41 is controlled by moving the Z-axis driving means 6 up and down in accordance with the value of the height data, so that the laser beam Lb is measured at the measurement position P (00, 00). The surface of the amorphous silicon layer Wa is just focused as shown in FIG. 7A or offset focused as shown in FIG. 7B (step S25).

  Hereinafter, the laser displacement meter 3 traces the measurement position P (00, 02) point, P (00, 03) point, etc., and measures the height displacement of those surfaces, and the height data is obtained. The CPU 53 sequentially writes the array position data and the height data from the memory 53 and writes them in the memory 53 sequentially in a two-dimensional array. The height displacement is calculated, and the height of the focus lens 42 of the laser barrel 41 is adjusted by height data corresponding to each height displacement.

  However, an abnormal value in which dust is present at the measurement position P of the amorphous silicon layer Wa and the height displacement data measured by the laser displacement meter 3 protrudes compared to the height displacement data measured before that. In such a case, for example, when there is a difference of 10 μm or more, the filter function provided in the CPU 52 is activated and no data is present. Therefore, the laser barrel 41 is annealed at the height (focus) at the previous measurement (processing) position to prevent abnormal heating.

  This laser processing apparatus 1 repeats the operation in the same manner in the second and subsequent rows. However, as described with reference to FIG. 5, when the laser displacement meter 3 traces the even-numbered column following the laser barrel 41, the height of the odd-numbered column immediately before the measurement by the laser displacement meter 3. Using the data, the computer 5 performs the above analysis and correction, controls the height of the laser barrel 41, and adjusts the focus of the laser beam Lb.

  In this manner, the entire surface of the amorphous silicon layer Wa is traced with the laser displacement meter 3 and the laser barrel 41 integrally, and annealing is performed.

  An amorphous silicon layer Wa having an area of 8 mm × 9.5 mm and a film thickness of about 50 nm to 120 nm is processed, and the surface of the amorphous silicon layer Wa is divided into a matrix at intervals of 0.5 mm to 15 × 18 (270 ) The measurement was performed at a point, and the movement speed (trace speed) in the X-axis direction of the XY-axis stage 2 was set to 100 mm / sec.

  Even when the glass substrate Wb is inclined and has a maximum inclination of ± 150 μm, the height displacement of the surface of the amorphous silicon layer Wa is measured by the laser displacement meter 3, and the laser barrel 41 to be calculated and controlled is controlled. It was within ± 8.

  The spot diameter of the focus of the laser beam Lb used was a rectangular spot of (0.4 mm to 05 mm) × (0.2 mm to 0.3 mm), and annealing was performed by just focusing on the surface of the amorphous silicon layer Wa. The annealing temperature at this time was about 800 to 1,000 ° C., and the entire surface of the amorphous silicon layer Wa was successfully annealed.

  As described above, the laser processing apparatus of the present invention can be used in the field of manufacturing liquid crystal display panels.

1 is a conceptual diagram of a configuration of a laser processing apparatus according to a first embodiment of the present invention. It is the perspective view which showed the trace method of the laser displacement meter and the laser barrel with respect to the surface of the amorphous silicon layer on a glass substrate. It is a conceptual diagram for demonstrating operation | movement of the laser displacement meter and laser barrel in the case of tracing the 1st row | line | column of the surface of the amorphous silicon layer shown in FIG. It is a conceptual diagram for demonstrating the 1st positional relationship and operation | movement of a laser displacement meter and a laser barrel when the trace of a laser displacement meter and a laser barrel transfers to the 2nd row from the 1st row. . It is a conceptual diagram for demonstrating the 2nd positional relationship and operation | movement of a laser displacement meter and a laser barrel when the trace of a laser displacement meter and a laser barrel transfers to the 2nd row from the 1st row. . It is a flowchart of operation | movement with the laser displacement meter and laser processing means in the laser processing apparatus of this invention. The focus state of the laser beam with respect to the processing surface is shown. FIG. A is a cross-sectional view showing a state in which the processing surface is just focused. FIG. B shows the state in which the processing surface is slightly offset and focused. It is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus of Example of this invention, 2 ... XY-axis stage, 3 ... Laser displacement meter, 4 ... Laser processing means, 41 ... Laser barrel, 42 ... Focus lens, 5 ... Computer, 51 ... Interface board, 52 ... CPU, 53 ... memory, 54 ... HDD, 6 ... Z-axis drive means, 7 ... Z-axis stage, Lb ... laser beam, W ... workpiece, Wa ... amorphous silicon layer, Wb ... glass substrate

Claims (6)

A displacement meter that sequentially measures the height of the surface at different positions of the workpiece and collects height displacement data;
Laser processing means that emits a laser beam that is disposed with a gap of at least the measurement point adjacent to the displacement meter and that heats the surface of the processing object;
Measured by the displacement meter, the control data generating means for generating a control data suitable to be processed height displacement data collected focus or offset on the front surface of the laser beam the workpiece of the laser processing means When,
A focus control means for controlling the focus of the laser beam from the laser processing means according to the control data,
When scanning the first line in the X direction from one end to the other end of the surface of the object to be processed, the displacement meter precedes the laser processing means, and when it reaches the other end, the displacement meter Reversing the scan direction by slightly shifting in the Y direction orthogonal to the X direction while maintaining the positional relationship of the laser processing means,
When scanning from the other end of the surface of the object to be processed toward the one end, the laser processing means is preceded by the displacement meter, and on a second adjacent line that is different from the first line. Scanning from the other end of the surface of the workpiece to the one end,
When the displacement meter scans prior to the laser processing means, the workpiece is measured with the control data from the control data generating means corresponding to each measurement point while sequentially measuring the measurement points with the displacement meter. When the laser processing means scans the surface prior to the displacement meter, the measurement points are sequentially measured by the displacement meter and stored in the control data generating means, and the laser processing means Is a laser processing apparatus for laser processing the surface of the object to be processed with the control data from the control data generation means corresponding to each measurement point obtained when scanning on the first line. The focus or offset of the laser beam on the surface of the object to be processed by the control data of the focus control means is performed by finely adjusting a focusing lens incorporated in the laser processing means in the vertical direction. Laser processing equipment.   The control data generation means includes a filter function for removing height displacement data of the abnormal value when an abnormal value is generated in the height displacement data measured and collected by the displacement meter. The laser processing apparatus according to 1 or 2.   The X direction and Y direction traces on the surface of the object to be processed by the displacement meter and the laser processing means are performed by moving and controlling an XY axis stage on which the object to be processed is placed in the XY direction. The laser processing apparatus in any one of Claims 1-3.   The laser processing apparatus according to claim 1, wherein the object to be processed is an amorphous silicon layer formed on a transparent glass substrate.   The laser processing apparatus according to claim 1, wherein the laser processing on the processing object is an annealing process.

Images